Abstract: The whiteness, paste viscosity, transparency, freeze-thaw stability and salt tolerance of cross-linking hydroxypropyl carboxymethyl starch (CHMS) were tested, and the molecule structure of CHMS was detected by FT-IR. Results showed that the cold paste viscosity was increased to 925mPa·s, the luminousness was up to 70. 7%, the freeze-thaw stability and salt tolerance of starch were also improved after been compound modified, while its whiteness was decreased to 90. 1%. New peaks were showed in the IR spectrogram, which proved the change of molecule groups of CHMS. Results above showed that, the preparation of CHMS could help to improve the value of tapioca starch in the industry.